LEV891 Biblical consideration for animals was the basis for the following laws: ... A mother animal and its young may not be slaughtered on the same day [this verse] Rabbi Aaron of Barcelona (13th cent.) explained this restriction as follows: "The purpose of this injunction is to instill in our character the quality of mercy and to remove ourselves from cruelty" (Sefer HaChinuch 294). To permit an animal to witness the killing of its young is an active of gross cruelty.